mod: copy stderr from ssh session to locally running processes stderr

Log the `serve` version in the beginning with a closing log message.

internal/serve/serve.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"os"
 	"os/signal"
@@ -56,14 +57,10 @@ func setupSshServer(host string, port string, host_key_path string, users map[st
 			func(next ssh.Handler) ssh.Handler {
 				return func(s ssh.Session) {
 					cmd := wish.Command(s, name, args...)
-					file, err := os.OpenFile("log", os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
-					if err != nil {
-						wish.Fatalln(s, err)
-					}
-					cmd.SetStderr(file)
 					if err := cmd.Run(); err != nil {
 						wish.Fatalln(s, err)
 					}
+					io.Copy(os.Stderr, s.Stderr())
 					next(s)
 				}
 			},
@@ -76,6 +73,9 @@ func setupSshServer(host string, port string, host_key_path string, users map[st
 // Serve an ssh application using the provided arguments.
 func Serve(host string, port string, host_key_path string, users map[string]string, name string, args []string) {
 	setupLogging()
+	log.Info("Running Serve (v2.7)...") // TODO make version string automatically the git tag (otherwise commit-hash)?
+	defer log.Info("Stopping Serve...")
+
 	srv, err := setupSshServer(host, port, host_key_path, users, name, args)
 	if err != nil {
 		log.Error("Could not start server", "error", err)